I tell my doctor everything, I don't know why people don't.
I do try to but I can see why this would make people feel comfortable. Sometimes doctors can be judging, or feel like they are judging you and you don't get that feeling from a computer. I know that sometimes my complaints about my health feel like they are something I shouldn't have bothered the doctor about and like they're insignificant even though I don't think logically that the doctor cares that much or is in any way judging. But with a computer you don't have those feelings and thus I see how this could help.
I judge my doctors. When I go to the doctors it's because I need them to perform a service. If they get off track with speechifying and moralizing I try to get them back on track. If I feel like their preoccupation with my less savory habits are getting in the way of dealing with my issues I don't go back to that doctor.
That is something I worry about when I go to the doctor even though that never has been an issue. The thing is that I really get how this could help both patients and doctors.